It has been found that reasonably stiff ski boot uppers and substantially nonbendable ski boot soles are required for skiing, except that the upper portion of the boot upper must be capable of being flexed forwardly and downwardly to accommodate the bending of the knees of the associated skier and the lower leg portions of the skier being forwardly and upwardly inclined relative to his feet.
Numerous manufacturers of ski boots have attempted to provide boot uppers which are stiff and do not flex, except in a direction to displace the upper portions of the uppers forwardly and downwardly as required. However, ski boots of this type are extremely difficult to walk in and accordingly a need exists for a ski boot upper and sole portion which is sufficiently stiff for proper support during skiing but which may be utilized in a conventional manner when walking.
Examples of previously known forms of ski boots including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 1,440,565; 3,597,862; 3,677,567; 3,694,937; 3,732,635; 3,775,875 and 3,924,869.
However, these previously known forms of ski boots are not capable of functioning, efficiently, when skiing as a stiff and supportive ski boot and also when walking as a ski boot which is sufficiently flexible to enable walking in the conventional manner.